Re: [Qemu-devel] [PATCH COLO-Frame v14 37/40] COLO: enable buffer filters for PVM

[Hailiang Zhang]

Hi Jason,

On 2016/2/18 11:46, Hailiang Zhang wrote:
> On 2016/2/18 11:31, Jason Wang wrote:
> > On 02/06/2016 05:28 PM, zhanghailiang wrote:
> > > Enable all buffer filters that added by COLO while
> > > go into COLO process, and disable them while exit COLO.
> > >
> > > Signed-off-by: zhanghailiang <address@hidden>
> > > Cc: Jason Wang <address@hidden>
> > > Cc: Yang Hongyang <address@hidden>
> > > ---
> > > v14:
> > > - New patch
> > > ---
> > >   migration/colo.c | 32 ++++++++++++++++++++++++++++++++
> > >   1 file changed, 32 insertions(+)
> > >
> > > diff --git a/migration/colo.c b/migration/colo.c
> > > index 235578b..86a7638 100644
> > > --- a/migration/colo.c
> > > +++ b/migration/colo.c
> > > @@ -104,10 +104,26 @@ static void secondary_vm_do_failover(void)
> > >       }
> > >   }
> > >
> > > +static void colo_set_filter_status(NetFilterState *nf, void *opaque,
> > > +                                   Error **errp)
> > > +{
> > > +    char colo_filter[128];
> > > +    char *name = object_get_canonical_path_component(OBJECT(nf));
> > > +    char *status = opaque;
> > > +
> > > +    snprintf(colo_filter, sizeof(colo_filter), "%scolo", nf->netdev_id);
> > > +    if (strcmp(colo_filter, name)) {
> > > +        return;
> > > +    }
> >
> > Checking by name is not elegant. As we've discussed last time, why not
> > let filter-buffer track all filters with zero interval in a linked list
> > and just export a helper to disable and enable them all? Things will be
> > greatly simplified with this, and there's even no need for patch 36.
>
> Yes, i know what you mean, but we have to add another
> 'QTAILQ_ENTRY() entry' like member into struct NetFilterState
> if we do like that, is it acceptable ?

Sorry for the hasty reply, ;)

We can use a list to store all the colo related buffer filters
without adding any member to struct NetFilterState.

The codes will be like:

struct COLOListNode{
    void *opaque;
    QLIST_ENTRY(COLOListNode) node;
};
static QLIST_HEAD(, COLOListNode) COLOBufferFilters =
   QLIST_HEAD_INITIALIZER(COLOBufferFilters);

void colo_add_buffer_filter()
{
    struct COLOListNode *filternode;
    ...

    filter = object_new_with_props();

    filternode = g_new0(struct COLOListNode, 1);
    filternode->opaque = NETFILTER(filter);
    QLIST_INSERT_HEAD(&COLOBufferFilters, filternode, node);
}

And we can track all the colo releated filters directly by
visiting the *COLOBufferFilters* list.

Thanks,
Hailiang

> > .